José Mourinho believes Tim Sherwood can have few complaints if he fails to retain his position beyond the end of the season and said it is "up to him" to convince the Tottenham Hotspur hierarchy to keep their young manager on.

Sherwood takes his Spurs side to Stamford Bridge on Saturday hoping to secure the club's first victory there since February 1990, a sequence that stretches to 26 games in all competitions, with his own future at White Hart Lane beyond the summer in doubt despite having signed an 18-month contract in December. Tottenham start the day four points adrift of the Champions League qualification places.

Louis van Gaal, who aspires to work in the Premier League once he leaves his position as the Holland manager after the World Cup, is in contention to take over while the Ajax coach, Frank de Boer, has also been linked with the position. Sherwood admits it has been "disappointing" to hear fellow managers comment on a potential job at Spurs, though Mourinho said the opportunity remains with the Englishman. "So now it's up to Sherwood," he said. "He has a chance. A chance that lots of people are waiting for. A chance. Now it's up to him."

Spurs remain in contention in the Europa League and in pursuit of the top four, with their rookie manager likely to have to succeed in one or the other if he is to retain his position. Mourinho has championed the cause of young English coaches in the Premier League in the past, though was quick to point out that, while he had embarked on his own managerial career at a new club with Benfica 13 years ago, Sherwood had at least benefited from being in a position of familiarity at Spurs having previously worked as their technical co-ordinator.

"I was not in the same position because, when I got my first job as a manager, I got it from not being in the club in another position," said Mourinho. "When I went to Benfica, I went from my house to Benfica. Not from the office or the under-21s or assistant coach. I arrived in the club to start my job. Sherwood has been in the club for a long time, so it's different."

Chelsea will monitor the fitness of Eden Hazard, David Luiz and Mikel John Obi before the derby, with only the Belgian expected to feature, despite suffering an ankle injury in midweek with his national team. Ashley Cole hurt the lateral ligament in his knee in training on Friday and will be absent for "a week to 10 days", according to the manager. The club hope he has suffered only a first degree tear. The 33-year-old had played 45 minutes for England in midweek but would have resumed his duties on the bench regardless with César Azpilicueta still first-choice at Chelsea.

Mourinho has never failed to win a league title when his team have topped the table in March, though he remains insistent that Manchester City should be considered favourites despite Chelsea having the opportunity to open up a nine-point advantage over Manuel Pellegrini's team on Saturday. City will have three games in hand and a superior goal difference.

"I'm not top of the league, that's the problem," added Mourinho. "I'm only really top of the league the day my team have played the same number of matches as the other teams, and I have more points. If that happens, I can say I'm top of the league. Until that moment, if other teams have matches in hand and can be top of the league if they win them, they are top of the league. So at this moment I'm not top of the league."